Can you re-drill a return hole?

Davy Jones

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Long story short, my SC Aquariums custom tank has returns drilled for 1/2" returns instead of 3/4" returns. Not a huge deal, but I can not find a reducing fitting at BRS to go from 1" return lines to 1/2" return for the bulk heads.

So my question is can i drill the hole larger? Or is that asking for trouble..?
 
Your return pump has 1" fittings and the bulkhead is 1/2"? Is that correct? Is the bulkhead threaded or slip? What pipe/tubing are you using for the return?
 
My return is 1"

The holes in my tank are drilled for 1/2" bulkheads and have a diameter of 1.25" best I can tell

Which is like ~2-3mm too small for a 3/4" bulkhead from what I can tell
 
Are you doing vinyl tubing or pvc plumbing?
 
I suppose You could, with great care. I wonder if you could sand the threads down but 2/3 mm's is a lot, wouldn't be any thread left. If Ya had a good guide to hold the bit until there was a proper groove started maybe?
 
I suppose You could, with great care. I wonder if you could sand the threads down but 2/3 mm's is a lot, wouldn't be any thread left. If Ya had a good guide to hold the bit until there was a proper groove started maybe?
Long shot, and idk anything about this stuff but can i sand it down some how? The return hole that is
 
That's an idea ! A dremmel with a fine grinding barrel ?
Might be bulky but maybe go from 1 down to 3/4 & again to 1/2 ?
 
I have drilled a 1/2" hole into a 3/4" hole on some pretty thin glas too (ADA-60F)
 
The problem with re-drilling a RR tank is MOST manufactures drill the holes and then temper the glass, but that is your big brand makers doing that, not sure about the smaller or custom builders.
 
Should I be concerned if it's a 1/2" return? There will be 2 of them and I have plenty of powerhead.

Reef savvy ghost overflow
Reef octopus varios 6 return
4 mp40s

You can see the return outlets in the below photos.

As for the manufacturer it's SCAquariums. I guess I didn't specify I wanted 3/4" returns when I asked for the tank to be built so it's not their fault
untitled.51.jpg
IMG_3983.jpg
 
If you’re splitting the returns, I think you’d be fine with keeping the the dual 1/2” returns. I wouldn’t want to risk damaging the tank by redrilling the holes. With 4 MP40s, you’ll have more than enough flow in the tank.

For the plumbing the 1” to 1/2” split, use a 1” true wye

https://flexpvc.com/cart/agora.cgi?p=PVC-Fittings-Wyes-TrueWye&p_id=413-4160&xm=on&ppinc=detail

and a couple of 1” to 1/2” reducers.

https://www.pvcfittingsonline.com/1...MI2Yq9g_TI2gIVxJCfCh2LTwEKEAQYASABEgI0G_D_BwE
 
If you’re splitting the returns, I think you’d be fine with keeping the the dual 1/2” returns. I wouldn’t want to risk damaging the tank by redrilling the holes. With 4 MP40s, you’ll have more than enough flow in the tank.

For the plumbing the 1” to 1/2” split, use a 1” true wye

https://flexpvc.com/cart/agora.cgi?p=PVC-Fittings-Wyes-TrueWye&p_id=413-4160&xm=on&ppinc=detail

and a couple of 1” to 1/2” reducers.

https://www.pvcfittingsonline.com/1...MI2Yq9g_TI2gIVxJCfCh2LTwEKEAQYASABEgI0G_D_BwE
Thanks waterdog,

Ill need to find something at home depot or menards, i need to get this setup and filled this weekend. Thanks for the help everyone!
 
For a tank that size i think 1/2" returns are more than appropriate. I would downsize your return pump, or have that large pump run into a manifold that supplies your skimmer, media reactor, fuge, etc.
 
For a tank that size i think 1/2" returns are more than appropriate. I would downsize your return pump, or have that large pump run into a manifold that supplies your skimmer, media reactor, fuge, etc.
As far as i can tell the varios 6 should be fine for my tank as i estimate about 10 feet or so of head loss after turns and fittings and the actual plumbing height. So max flow out of the pump would be roughly 900gph at 100% and that is then split between 2 returns for 450gph a side. give or take 10% or so either direction.
 

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